A vehicle generally has a number of zones around the vehicle that are not visible to a driver either by direct line of sight or by the use of mirrors. During various driving situations, however, it may be necessary for a driver to view these zones in order to identify potential obstructions or obstacles, such as other vehicles, pedestrians, street signs or posts, and many other possible obstructions or obstacles.
In order to improve the visibility of particular zones around the vehicle, one or more cameras may be installed in order to view the vehicle surrounding. The images captured by the cameras of these systems are typically viewable on a display installed in the instrument panel of the vehicle. Then, the driver may have a better understanding of zones around the vehicle that are hidden from direct view or view by the use of mirrors.
Often, however, the images captured by the cameras of these systems have an unnatural appearance that may be difficult for a driver to understand. For example, cameras installed around a vehicle may utilize wide angle optics. Although these wide angle optics may allow the cameras to capture a larger area of the vehicle surrounding, they may also create distortion in the images. Thus, a driver may have difficulty understanding the vehicle surrounding or judging distances to objects in the images of the vehicle surrounding because of the distortion. For example, FIG. 2 shows a representative drawing of a typical point of view from a rear view camera system using wide angle optics while driving a driven vehicle 8 on a roadway 9. As can be seen from FIG. 2, the image of the rear view shows the roadway 9 and a following vehicle 10 behind the driven vehicle 8. However, this image is highly distorted, making it difficult to accurately judge distances to objects within the image.
In addition, cameras may be mounted at locations around the vehicle that are not intuitive to a driver. Thus, a driver may have difficulty understanding the perspective of the images or judging distances to objects in the images of the vehicle surrounding because of the unexpected mounting locations of the cameras.
For example, when reversing into a parking spot, a driver viewing an image from a rearward facing camera using wide angle optics may have difficulty understanding the perspective of the image or judging the distances to obstacles, such as pillars, other vehicles, and curbs, due to distortion and/or unexpected mounting locations of the cameras.
Further, FIG. 3 shows a representative drawing of a typical point of view from a side view camera system using wide angle optics while performing a parallel parking operation of a driven vehicle 8. As can be seen from FIG. 3, the image of the side view shows a parallel parking spot 11, a sidewalk curb 12, and a parked vehicle 13 behind the driven vehicle 8. However, this image is highly distorted, making it difficult to accurately judge distances to objects within the image.
In order to minimize the effects of unusual points of view, systems having cameras may also include sensors installed in various locations. These sensors may provide additional information to aid a driver in understanding the images captured by the cameras. For example, the additional sensors may measure distances to objects in the captured images.
Other systems may utilize cameras with wide angle optics but display only portions of the images to reduce the confusing effects of wide angle fields of view. In addition, some systems may indicate to a driver the measured distances graphically and numerically, such as by the use of labeled graphic lines superimposed on the images, so that a driver may better judge distances to objects in the images.
Japanese Published Patent Application No. 2001-224013 describes a drive support system that visually displays distance information between a vehicle and an obstacle. The visual display may be from a manually-specified perspective to easily view the relative positions of the vehicle and the obstacle. In addition, the obstacle may be color-coded based on the distance to the vehicle, in order to further visually display the distance information.
German Published Patent Application No. 10 2005 002 636 describes a system that combines video data and distance data by a coordinate transformation from a camera coordinate system to a distance coordinate system, such that the video data and distance data are aligned in a single coordinate system.
U.S. Patent Application Publication No. 2003/0088361 describes a system including an image-measured distance detection device for detecting distance data, and a laser-measured distance detection device for detecting distance data. In addition, a three-dimensional object recognition means recognizes an object in front of the vehicle based on the distance data from both the image-measured distance detection device and the laser-measured distance detection device.
German Published Patent Application No. 31 06 100 describes an obstacle warning device in which the obstacles are color coded depending upon the obstacle distance or obstacle speed.
U.S. Patent Application Publication No. 2003/0035050 describes a driving assistance display apparatus for displaying an image from a wide angle camera on a single screen so that a driver can intuitively understand the image. In this regard, the display apparatus splits the single screen into a plurality of sub-screens corresponding to inner faces of a polyhedron.
U.S. Patent Application Publication No. 2002/0181803 describes a perspective projection image creation system including an optical system, an imaging section, an image transformation section, a scale model creation section, an image combining section, and a display section. In addition, the image transformation section transforms the image data to a perspective projection having a projection center at a focal point of a hyperboloidal mirror of the optical system. Further, a first omnidirectional vision sensor is positioned at the right front of the car, and a second omnidirectional vision sensor is positioned at the left rear of the car.
U.S. Patent Application Publication No. 2006/0088190 describes a driving support system including a plurality of image taking devices that take images of areas around a vehicle. Then, an image processing unit performs a predetermined coordinate transformation to produce a virtual image viewed from a virtual viewpoint.
U.S. Patent Application Publication No. 2007/0003108 describes an image display device having plural cameras for capturing plural images. Then, the image display device forms a bird's eye view showing the vehicle surroundings. Further, a driver may select a view of one of the plural cameras. In addition, a contactable region may be flickered or highlighted based on the distance or approaching speed of the obstacle.
Japanese Published Patent Application No. 2004-274114 describes an image display apparatus that displays a viewpoint-converted image. The apparatus may also display a warning line, or other alarm display, based on a distance to an obstacle.